1. Field of the Invention
This invention relates to surgical devices and procedures for their use for implanting the surgical device in a patient during a surgical procedure to dispense a chemical to a site of that procedure for a period of time thereafter.
2. Prior Art
In a surgical procedure where a part of a human body is opened and a procedure performed thereon, it is common to apply an antibiotic, chemical deadening agent, growth stimulator, chemotherapeutic agent, radioactive isotope, or the like, onto the site of that procedure prior to closing to provide for infection control, pain control, and for other chemically-mediated biological response. In an orthopedic surgical procedure it is often necessary to open the skin to a bone surface or cortex to perform a procedure, such as one involving a joint replacement, fracture reduction, or the like, which bone site or location is particularly prone to infection after closure. Where such infection is present, often large to even massive doses of antibiotics are required to be taken, orally or by injection, to overcome such infection. Such doses themselves often create undesirable side effects.
The present invention, by providing for dispensing an appropriate chemical agent or agents to an actual site of such treatment, limits the amount of such chemicals as needed to overcome the infection or provide treatment, thereby minimizing the likelihood of unwanted side effects. In addition to passing an antibiotic, or like chemical, onto a surgical site, for infection control, or other treatment, the devices and procedures of the invention can also be used for dispensing a local anesthetic agent, or the like, to that site, to minimize a patient's discomfort during healing. Additionally, the invention can also be used to deliver local growth factors to the site to encourage healing, or chemotherapeutic agents to destroy unwanted cells, such as cancer cells.
Certainly, applications of chemical agent onto a site of a surgical procedure prior to closing are not new. Also, arrangements for providing a medication conduit to a potential injection site have been in use. For example, an article presented in "The Journal of Arthroplasty", titled, Treatment of Acutely Infected Arthroplasty With Local Antibiotics, Vol. 6, No. 2, dated June 1991, pages 179-183, sets out an implantable reservoir with a feed conduit into a surgical site is shown as having been used on a number of patients. Further, such an implantable reservoir and feed conduit connecting into the vena cava has been used as a substitute for a peripheral venous catheter to provide long term infusion support is currently in use and is known as a porta-cath or central line. Such other devices and arrangements, however, unlike the present invention, have not involved a range of implantable devices to be positioned directly on or closely adjacent to a site of infection, injury, or tumor, to pass a chemical agent therefrom. With the devices or the invention and methods for their use chemical agents can be delivered through a connecting line from a reservoir maintained at or just below the patient's skin surface. Further, such implants, as those of the invention can be made to be biodegradable to be absorbed by the body after removal of the transmission line.